“I just wanted to congratulate you because I am hearing of the unbelievable job on the drug problem,” said Trump on the call with Duterte, which was otherwise focused on security issues related to North Korea. “Many countries have the problem, we have a problem, but what a great job you are doing and I just wanted to call and tell you that.”

When Duterte said that his drug war is necessary to "preserve his nation," Trump agrees with him and then seems to criticize former President Barack Obama for failing to grasp that point. Trump said that Obama, who publicly condemned Duterte's bloody drug war, "did not understand."

"I understand that and fully understand that, and I think we had a previous president who did not understand that, but I understand that and we have spoken about this before," Trump said.

The Trump administration has signaled a tougher drug stance at home.

Attorney General Jeff Sessions sent a memo earlier this month that ended an Obama-era initiative aimed at reducing sentences for non-violent drug offenders and lowering rates of mass incarceration. On May 12, Session spoke about the changes at the Justice Department.

“We are returning to the enforcement of the law as passed by Congress — plain and simple,” he said.